566 abstracts: geology 



sented by the alluvium of the lowlands and valleys, by high gravel and 

 silt terraces, and in the higher mountains by local glacial deposits. 

 The metamorphic series is intensely deformed and the Cretaceous strata 

 also exhibit complex structures. 



There is clear evidence that very extensive changes of drainage have 

 taken place during Quaternary times. This is believed to have been 

 due to the advance of glaciers from the mountains which bound the 

 central Yukon region. The terraces are believed to have been formed 

 in lakes caused by ice damming. A. H. B. 



GEOLOGY. — Natural gas resources of parts of North Texas. E. W. 



Shaw, et al. U. S. Geological Survey Bulletin 629. Pp. 129, 



with maps, sections and illustrations. 1916. 

 The examination on which this report is based was instigated by the 

 citizens of Dallas and Fort Worth, for the purpose of getting informa- 

 tion as to the sufficiency and the prospective duration of the gas re- 

 serves within reach of these cities. The two reports contained in this 

 volume describe not only the geology of several gas fields but also 

 discuss the original quantity of the gas, the present capacity and the 

 probable life of the fields. Areas that are worthy of prospecting with 

 the drill are pointed out and it is concluded that the Petrolia field from 

 which the present supply is being drawn would last the cities only 3 

 or 4 years. The other known pools of Texas being small it becomes 

 necessary either to discover new gas pools or to lay pipe lines to those 

 of Oklahoma. E. W. S. 



GEOLOGY. — Petroleum withdrawals and restorations affecting the public 

 domain. Max W. Ball. U. S. Geological Survey Bulletin 623. 

 Pp. 427, with 9 maps. 1916. 

 This bulletin contains true and accurate copies of orders of with- 

 drawal, restoration, modification and classification and of the more 

 important correspondence leading to changes of policy regarding these; 

 an index to the orders, township by township ; a short statement of the 

 purpose of the withdrawal policy; and a brief review of the history of 

 oil withdrawals. In addition, it includes a chapter on oil-land law, 

 giving the statues and decisions, judicial and departmental, which may 

 be of most interest to the oil operator on the public domain. It is 

 accompanied by maps showing the areas withdrawn in each state — 

 Arizona, California, Colorado, Louisiana, Montana, North Dakota, 

 Utah, and Wyoming — where oil withdrawals were outstanding January 

 15, 1916). R. W. S. ' 



